Actually this can be done without loss of precision. I cheat a lot of times when asked to generate a function that matches a series. If the series is a polynomial simply solve for the coefficients.
z=.4 9 15 22 30 39 49 60 72 85 z%.(i.#z)^/i.6x 4 9r2 1r2 0 0 0 ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
